Automatic control of railway classification yard switches



Oct. 27, 1959 J. G. KARLET ETAL 2,910,578

AUTOMATIC CONTROL OF RAILWAY CLASSIFICATION YARD SWITCHES 2 Sheets-Sheet1 Filed Dec. 23, 1955 WE m m @SB N w Z QQ F QQ Q wxg A SP QQ QQQ WN 88 Qg Q gww wm N NQ .Nw w mg QQSMQN A WEN Al 88 EE NNQMN QN -NQ -B--W W SQNNnmwmkwwa w w H @q fib m mg Qw TIA w I l i fiww \QGYN wwa m S N d9 Y, Mmm mum m b .E m m A;

United States Patent AUTOMATIC CONTROL OF RAILWAY CLASSI- FICATION YARDSWITCHES Application December23, 1955, Serial No. 555,095

5 Claims. (Cl. 246-4) Our invention relates to the automatic control ofrailway classification yard track switches. More particularly, ourinvention relates to the automatic substitution of a preselected routein place of a previously designated route for a railway car in anautomatic switching system for such a classification yard, thissubstitution of routes taking place automatically following a singleaction on the part of the yard operator.

Automatic switching systems for railway classification yards in generaluse at present provide for the storing of the routing for successivecars or cuts of coupled cars which are to pass over the hump and moveunder the influence of gravity to the various tracks in theclassification yard. These routes are stored generally by the operatorof the yard selecting, from a bank of push buttons, the finalclassification trackuumber to which the particular car or cut is totravel. The routes may also be inser'ted into the apparatus directlyfrom printer tapes or by other automatic devices. Such routes are storedin a series of initial storage banks until the corresponding cut of carsis ready to move over the first switch in the yard, after which theroute is transferred from the initial storage banks to the storage banksassociated with the next switch to which the car is traveling and thencesuccessively transferred to the various other switches along the routedesignated for that car. The various switches are controlledautomatically through the influence of the stored route as it istransferred to the various switch locations and as the corresponding cutof cars approaches that particular switch. Such systems and theirautomatic operation are Well known in the general art.

These systems furthermore usually provide for the cancellation of thevarious stored routes and the insertion of new routes as changes in theoperation become necessary. Thereare two methods in general use by whichthe new routes may be inserted. The first method calls for a generalcancellation of all the routes stored in the initial storage banks, ofwhich there may be as many as five such routes, and the inserting againin proper order of a route for each of the cancelled routes with thenecessary corrections being introduced during the new storage action.The other method calls for a cancellation of the individual routesstarting with that route most recently stored, and cancelling one at atime in the reverse order of storage until the incorrect route iscancelled. The new corrected routes are then inserted in the order thatthe cars will pass over the initial switch. Either of these operations,it may be seen, requires considerable time and effort on the part of theoperator. Particular care is necessary that the proper cancellations aremade and that the new routes are inserted in the correct order.

At some classification yards, special operations are required in theeveryday operation of that particular yard. For example, it may be arequirement that each car passing over the hump and traveling into thevarious classi: fication tracks must be weighed. This is generally doneby a track scale capable of weighing the moving cars and located betweenthe hump and the initial switch to the Patented Oct. 27, 1959classification yard tracks. In such a case, the trains to be classifiedmust be separated into individual cars which then are weighed as theymove across the track scale prior to their passage over the firstswitch. The route for each car is generally stored in the initialstorage bank as that particular carreaches the crest of the hump. Inother words, the routes are stored prior to the time that the car passesover the track scale. As a result, in such yards, the frequency at whichchanges in routing are required is rather high by comparison witha yardwhere such weighing is not a requirement of general operation. Forexample, it will frequently occur that a car is not properly weighed oris not weighed at all as it crosses the track scale. Such cars mustlater be returned to the hump and again passed over the scale in orderto be properly weighed. Therefore, it is a definite advantage if suchcars can be routed to a holding track from which they may be pulled backand again pushed over the hump. This eliminates the necessity forseparating them from other cars which were properly weighed and properlyclassified. The cancellation and insertion of a new route for each ofthese cars which is not properly weighed requires time and efiort on thepart of the operator all out of proportion to the general operation forwhich he is responsible. In fact, it has been found that unless specialmeasures are provided, such cancellation and the insertion of newroutes. hinders the regular operation of the yard, reducing the timewhich the operator can spend in handling the storage of routes andobserving the regular movement of the cars tothe various classificatiotracks.

Thus a definite advantage can be realized in the operation of such yardsby having a method by which a single action on the part of the operatorinitiates an automatic sequence of operations which cancels thepreviously designated route for a particular car and substitutes, forthat designated route, a preselected route to a holding track. It ispossible in these cases to preselect this special routing since theholding track or, as it is known in one railroad, the .blow-ou-t.=track.is the same for all diverted carswhich are not properly weighed. Inother words, any car which is notproperly weighed is diverted to aparticular track designated for such ,cars. From this track the carsmay, as time permits, then be pulled back and again pushed over the humpfor proper weighing and proper classification. However, a system I:providing such substitution can also be used to divert cuts, in aregular classification yard, which may have joined or coupled togetheras they move through the yard prior to reaching their final destination.Such coupled cuts are generally allowed to follow the designated routeof the first of the two outs, and the route for the second cut iscancelled out. The second cut must then be later separated from a stringof properly classified cars and itself properly placed. However, if thetwo coupled cuts were diverted to a particular hold-track, it would bemuch easier and quicker to later pull both of the cuts back for properclassification without having to separate them from other cars whichwere originally properly classified.

It is thus an object of our invention to provide means, in an automaticswitching system for railway classification yards, which will quicklyand simply substitute another route for the previously designated routefor a particular cut of cars.

A further object of our invention is to pr-oviderneans in such anautomatic switching system to permit the operator, by a single action onhis part, to substitute a preselected route for the designated route fora particular cut of cars.

Another object of our invention is to provide means to cancel thedesiguatedroute stored for a car approaching 3 an automaticallycontrolled switch and substitute for that car a preselected routingbeyond that switch.

A still further object of our invention is to provide means for theoperator of an automatic switching system for railway classificationyards, by a single action, to cancel the route stored in the storagebanks for a car approaching a switch and substitute a preselected routewithout disturbing the remaining routes already stored in the storagebank for succeeding cars.

Other objects and features of our invention will be obvious from thefollowing description and the appended claims.

In accomplishing the various objects and features of our invention, weprovide, on the control panel for such an automatic switching system, asingle push button which the operator may push in order to substitutethe holdtrack route and divert the corresponding car to such a track.Other means may or may not be provided, as a railroad desires, to selectfrom time to time between various tracks in the yard for the hold-trackassignment. Thesubstitution .push button operated by the yard operator,in his single required action, controls a stick relay which remainsenergized until the substitution of the hold-track route is completed.This stick relay is used to cancel the designated route, for a car orcut of cars which is to be'diverted, stored in a route storage bank forthe switch toward which the particular car or cut of cars isapproaching. This stick relay is further used to prevent the transfer ofthe route held in the next preceding storage-bank, since this transferoperation would normally automatically occur as soon as the particularstorage bank is empty. Instead, with the push button repeater stickrelay energized and the storage bank clear of any storage due to thecancellation, a storage insertion relay is energized and is then heldenergized by the push button stick relay until the substitution actionis complete. This storage insertion relay prepares the particularstorage bank to receive a new storage by reenergizing the storagedetector relay for that bank. The insertion relay then further energizesthe proper route storage relay or relays for the hold-track routing. Theenergized storage relays are then held energized in the usual manner bythe storage detector relay for that bank. When the route storage relaysare energized, the track switch will be properly controlled to route theapproaching cut of cars to the selected hold-track. With a route storagerelay and the detector relay for the particular bank picked up, and thehold-track stick relay and the storage insertion relay also picked up, afunction-complete relay is then energized. The energizing and resultingpickup of this function-complete relay causes the various substitutionrelays to be reset to their normal, deenergized position, returns theentire apparatus to its normal condition, and allows the usual sequenceof operation to then continue. Thus, as will be described in more detailshortly, the single action of the operator in pushing the holdtrack orsubstitution push button cancels the previously designated route for theapproaching car, prevents the transfer of the next succeeding designatedroute into the empty storage bank, substitutes the routing to theholdtrack for that approaching car, and, when this substitution iscomplete, resets the apparatus to its normal condition to permit thecontinuation of the normal sequence of operation.

We shall now describe a single form of apparatus embodying the featuersof our invention, and shall then point out the novel features thereof inthe appended claims.

Referring now to the drawings, Fig. 1 is a diagrammatic view of a smallclassification yard which is provided with an automatic switchingsystem. Fig. 1 also shows the flow plan for the route storages from thecontrol panel through the initial route storage banks at the firstswitch for the yard, indicating the manner in which the hold-track routeis subs -tilted into the bank of the.

initial storage banks.

Fig. 2 is a diagrammatic view of one form of apparatus which embodiesthe features of our invention when applied to the automatic switchingsystem for the yard shown in Fig. 1.

In each of the drawings similar reference characters refer to similarparts of the apparatus.

Referring now to Fig. 1, a railway classification yard is shown havingsix classification tracks. As indicated in the drawing, tracks 1 and 2are designated as holdtracks but these tracks may also be used at timesfor the regular classification of cars. It is to be understood that thehold-track in a classification yard may be a special track which has noother designation and which is not normally used for the classificationof cars. It is also to be understood that our invention may be appliedto any size classification yard, especially those having a greaternumber of tracks than the number shown in this particular figure. Inother words, for purposes of this application, the classification yardin Fig. 1 is greatly simplified over those in general use on railroads.A track scale is provided on the lead from the hump to the first switchfor the purpose of weighing each car passing into this classificationyard. Cars roll singly, under the influence of the force of gravity,from the hump which is to the left of the drawing, over the track scale,and into the classification tracks at the right of the yard shown. Eachcar is weighed as it passes over the track scale. In the operation ofthis classification yard, these cars are diverted by the five switchesshown into one of the six classification tracks. All cars of necessitypass over the switch designated 16SW. This switch is controlled by aswitch motor 16 shown in block form in the drawing. It is understoodthat this switch motor may be of any form well known in the art. Forexample, it may be either an eleo tric motor or an electropneumaticswitch movement. Each switch in the yard shown is similarly equippedwith a similar switch motor but such motors and their controls are notshown for simplicity.

The switch motor 16 is controlled to operate switch 1-6SW to its normalor reverse position by the relays in bank A, as indicated conventionallyby the dotted line, of the initial storage banks of the automaticswitching system with which this classification yard is provided. Asindicated diagrammatically in this drawing, the designated routes areinitially stored in bank C, being inserted therein directly from thecontrol machine as selected by the yard operator. The route storagesthen advance successively into bank B and into bank A as thesesucceeding banks become empty. When a car passes over the switch 1-6SW,the corresponding route stored in bank A is then transferred to thesimilar storage banks for the next switch location along the route beingfollowed by that particular car. The apparatus for this operation is notshown herein in detail since it is not part of our invention. For acomplete description and showing of such an auto- 1 matic switchingsystem, reference is made to the copending application for LettersPatent of the United States, Serial No. 355,281, filed May 15, 1953, nowUS. Patent 2,863,991 granted Dec. 9, 1958 by Benjamin Mishelevich, forAutomatic Control of Railway Classification Yard Track Switches.Acomplete description and 1mderstanding of the automatic switchingsystem may also be obtained from Manual 517, entitled, fAutomaticSwitching for Classification Yards, published January 1953 by the UnionSwitch 8; Signal Division of Westinghouse Air Brake Company. Since acomplete description of the automatic switching system may be obtainedeither from the above-mentioned copending application or from Manual517, it is not necessary to herein provide a complete description of theoperation. Only such operation and apparatus as is necessary for anunderstanding-of our invention is thus shown and described herein.

Referring again to Fig. 1, if a car passing over-the track scale is notweighed, the operator is instructed to divert that particular car to thehold-track then in use for diverted cars. As previously mentioned, theoperation of the hold-track push button causes the route, for theapproaching car, then stored in bank A of the initial storage banks tobe cancelled. At the same time, the routes stored in banks B and C areheld, that is, their transfer to bank A is prevented. Then thepreselected hold-track route is inserted into bank A and the switch16SW,is operated, in this case, to its reverse position. The substitution apparatus is then reset and the automatic switching apparatusallowed to continue its normal sequence of operation. As this car passesover switch 1-6SW, the hold-track routing is transferred to the storagebanks for switch 1-2SW to which the diverted car is traveling. As theroute storage for the diverted car is transferred to the next storagebanks, the route storage in bank B for the following car is transferredto bank A and the normal operation continues. It is to be understoodthat the substitution of the preselected hold-track route may beaccomplished in any storage bank. For simplicity, this presentdescription deals onlywith the A bank.

Referring now to Fig. 2, there is shown apparatus embodying the featuresof our invention that are necessary for the automatic switching systemfor the classification yard of Fig. 1. Most of the apparatus shown inFig. 2 is that relating to or associated with bank A of the initialstorage banks of the automatic switching system. However, contacts ofseveral relays in the B bank of the initial storage banks are also shownas they are included in circuits necessary for the operationof thesystem of our invention. One other circuit, to be described in moredetail later, extends through the storagebanks for other switchlocations. Again, in this figure of thedrawings, only those circuits andthe apparatus necessary for a discussion of the operation of theapparatus as it embodies our invention are shown.. For a completedescription and showing, reference is again made to the aforementionedMishelevich copending applicationor to Manual 517.

The apparatus of the automatic switching system is provided with asource of direct current, such as a battery, which is not shown in thedrawing for simplicity. However, the positive and negative terminals ofthe source, when shown, are designated by the reference characters B andN, rmpectively.

The apparatus of Fig. 2 will now be described generally before taking upthe detailed operation of the substitution of the preselected route. Therelays A1C to A6C, inclusive, shown at the right of Fig. 2, are theroute storage relays for bankAof the initial storage'banks.

In the present application, each relay is associated with a particularclassification track. For example, relay AlC is associated particularlywith track 1 and any time that relay AlC is energized and picked up, theroute to classification track 1 1's, stored in this particular bank. Itis to be understood that in a larger classification yard, additionalstoragerelays would be necessary in this and other storage banks. Infact, as shown in Manual 51 7,,where more than ten classification tracksare. included, it is the practice to usetWo relays to store, the ;routefor each classification track, It is to be understood also that thesystem of our invention may be applied to such larger classificationyards with a greater number of tracks and that, for simplicity only, thetracks in the present showing have been limited to six.

During normal operation of the system, that is, when no substitutionoperation is in progress, the storage relays are energized over contactsofthe similar storage relays in bank B of the initial storage banks Onlythe contacts of these storage relays of the B bank that are included inthe energizing .eircuits for the A bankstorage relays are shown in thedrawing in order to make easier to understand the system of ourinvention. A typical circuit for. energizing one of the storage relays,for example,

relay A6C, may be traced from terminal B. at. frontcontact a of transferrelay AT, over front contact a ofirelay B6C, back contact a and thewinding of relay A6C, and front contact a of storage detector relay ADto terminal N. When relay A6C picks up, a stick circuit is com! pletedfrom terminal B at its front contact a including the winding of therelay and front contact a. of relay AD. The transfer contact a of eachof these storagerelays is of the type known as a continuity or makebefQrebreak contact. This is indicated in the drawing by the short areshown near the end ofthe armature of the particular contact for each ofthese relays Thus the stick circuit for each relay is completed prior tothe interruption of the initial energizing circuit at itsback contact a.It will be noted here that the similar energizing circuits for relaysAIG and AZC each also include a back contact of a relay SI. The purposeof these back contacts and the corresponding front contacts will bedescribed shortly, but for normal operation these back contacts remainclosed and thus have noeffect upon the energizing circuits.

The transfer relay AT here shown is identical with the transfer relayshown in the aforementioned Manual 517 in the general automaticswitching systems. This relay is energized and picks up whenever atransfer of a route storage is to be made from the B bank into the Abank. The energizing circuit for relay AT may be traced from terminal Bover back contact a of a relay BT and front contact a of a relay BD,both in storage bank B, back contact b or relay AD, back contact b of arelay HTS, and the winding of relay AT to terminal N. The contacts oftransfer relay BT and storage detector. relay BD of storage bank B areincluded. in this circuit, as explained in the before-mentionedreferences to determine that there is a storage in bank B'to be,transferred and that no transfer operation into bank B is .in progress.This energizing circuit for relay AT differs slightly from those shownin the references by including back contact-b of the relay HTS. Theutility of this back contact will appear hereinafter during thedescription of theoperation of the system. The closing of front contactb of relay AT completes an obvious stick circuit bypassing back contactb of relay AD. This stick circuit is effective to retain the relayenergized until the transfer of the route storage from bank B to bank Ais complete, which will be indicated by the releasing of relay BD toopen its front contact a. v

The storage detector relay AD is used to detect or indi: cate thepresence of a route storage in bank A. As shown in describing theenergizing circuit for relay A6C, relay ADmust be energized so that itsfront contacta is closed in order to complete the energizing andthestick circuits for the route storage relays. During the normal operation of the system, relay AD will be energizedfrom terminal B over aback contact 10, which is closed except when a general routecancellation is called for by the operator, from contact 0 of relay AT,back contact c of relay HTS, the winding of relay AD, and thence overback contacts, in multiple, of the transfer relay T and the detectorrelay D in each of the next succeeding storage banks, in series, toterminal N. When relay AD picks up and closes its front contact 0,a'stick circuit is completed for that relay which by-passes frontcontact 0 of relay AT, so that the detector relay AD willrem ainenergized when transfer relay AT is released upon completion of thetransfer operation.

The back contacts of the transfer and detector relays of the succeedingstorage banks are included in the circuit for relay AD in order toprovide a release for this relay when the transfer of the route storageis made from bank A to. the storage banks associated with the succeedingswitches in the various routes beyond this first switch. Therefore,contacts of these relays in the. storage banks at the switches 1 -2SW.and s-ssw are included in are aroute' 'stor'ag'e is transferredeither to the storage bank at switch 1-2SW or to the storage bank atswitch 3-6SW. Relay AD is oftheslow release type so that its frontcontacts will remain closed until the transfer operation is complete,although the relay winding may be deenergized.

'It is to be noted that a back contact of relay HTS is included in theenergizing circuit and in the stick circuit for relay AD, the purpose ofwhich will appear in the following discussion. As part of our inventiona second energizing circuit is also provided for relay AD which may betraced from terminal B at back contact over front contacts of a relay SIthrough the winding of relay AD and as previously traced to terminal N.The utility of this circuit will also appear shortly.

-In providing the features of our invention, we have added to thegeneralautomatic switching system the holdtrack lever HT, thesubstitution or hold-track push button HTPB, the hold-track stick relayHTS, the storage insertion relay SI, and the function-complete relay PC.As indicated by the dot-dash rectangle enclosing the holdtrack lever andpush button, lever HT and push button HTPB are'mounted in the controlmachine near the bank of push buttons by which the operator may selectthe classificationtrack to which the various cuts are assigned. The holdtrack lever HT is provided to allow a selection between tracks 1 and 2as the destination of cars which must be diverted from the normalswitching operations. This selection between'two or more tracks as ahold-track assignment may or may not be provided as is desired by therailroad making the installation. As previously mentioned, thehold-track may also be a separate track not normally used to receivecars being classified, but used only for the purpose er receiving thediverted cars. The hold-track push button is provided as a means forinitiating the substitution operation which diverts a particular car tothe hold-track. The yard operator need only actuate this push button toclose its contact a to initiate the entire operation.

The hold-track stick relay HTS repeats the operation ofthe hold-trackpush button HTPB, but only if a route is stored inthe A bank. Thecircuit for energizing relay HTS may be traced from terminal B overcontact a of push button HTPB, front contact d of relay AD, and thewinding of relay HTS to terminal N. When relay HTS picks up, the closingof its front contact a completes a stick circuit for this relay whichincludes back contact a of relay FC. As will develop hereinafter, thisstick circuit is eifective, so that relay HTS remains picked up, untilthev substitution operation has been completed. When relay HTS picks up,it also interrupts various other circuits at its back contacts 12 and cas will appear during the description of the general operation of thesystem.

The storage insertion relay SI is energized when the conditions arefulfilled that a substitution is requested and the designated routecancelled, that is, relay HTS picked up and relay AD released. Thecircuit for relay SI may be traced from terminal B over front contact dof relay HTS, back contact e of relay AD, and the winding of relay SI toterminal N. Closing of front contact a of relay SI completes a stickcircuit which by-passes the back con tact of relay AD, but includesfront contact d of relay -HTS. Relay SI when picked up to close itsfront contacts causes the preselected hold-track route to be insertedinto storage bank A. Again, this operation will be described later.

The function-complete relay PC, which is used to indicate that thesubstitution operation has been completed, is not energized until all ofthe conditions of the substitution have been .met. Thus the energizingcircuit for relay FC may be traced from terminal B over front contact cof relay AIG and right-hand contact b of lever 'HT, or over frontcontact c of relay A2C and left-hand contact b of lever HT, and thenceover front contact d ofrelay SI to indicate that the storage insertionis complete, front contact f of relay AD to indicate that the hold-trackroute is stored in bank A, front contact e of relay HTS to indicate thatthe substitution has been called for, and through the winding of relayFC to terminal N. When relay FC picks up, opening of its back contact astarts the resetting action of the apparatus t0 return the system to itsnormal operation, as will be shortly described. Since only a singlecontact of relay PC is used to initiate the resetting action, theenergizing circuit for this relay could be used, by proper modification,to initiate the resetting action and relay FC eliminated. While ourinvention contemplates such a modification, for simplicity only thearrangement using relay PC will be discussed.

We shall now describe the operation of the apparatus in substituting thehold-track route for a previously designated route for a car that isapproaching the track switch 1-6SW. We shall first assume that thedesignated route for the car approaching the first switch is totrack 6.Under this condition, when the route storage for the approaching car hasbeen transferred into bank A of the initial storage banks, relay A6Cwill be energized and will be held energized by its stick circuitpreviously traced, the stick circuit including front contact a ofdetector relay AD. Relay AT remains released at this time since itsenergizing circuit is open at back contact b of relay AD. Relay AT wasdeenergized and released when its stick circuit was interrupted by therelease of relay BD at the completion of the route transfer into bank A.It is assumed also that the route for a following car is at this timestored in bank B, but because front contact a of relay AT is open, theclosing of a front contact a of one of the relays B lC to B6C isineffective to energize the corresponding relay in the A bank. RelaysHTS, SI, and PC are at this time in their normal, deenergized conditionas shown in the drawing. a

It is now assumed that this car approaching switch 1-6SW is incorrectlyweighed as it passes over the track scale shown in Fig. 1. The operatoris immediately instructed to divert this car to the hold, or blow outtrack. Upon receiving these instructions, and when his route storageindicator shows that the designated route for the car not weighed hastransferredto bank A, the

yard operator pushes the hold-track push button HTPB. Having performedthis action, the operator is then free to proceed with other business inthe operation of the classification system. Closing of contact a of pushbutton HTPB immediately energizes relay HTS, since front contact d ofrelay AD is closed because of the route storage existing in bank A.Relay HTS, having picked up, completes its stick circuit and remainsenergized.

The opening of back contact 0 of relay HTS interrupts the stick circuitfor relay AD and this relay shortly releases at the end of its slowrelease period. When relay AD releases, the opening of its front contacta interrupts the stick circuits for the route storage relays and thosewhich have been energized are released. In the present case, relay A6Cwas assumed to be picked up and it is now released to cancel the routestored in bank A for the approaching car. The release of relay A6Cclears the A storage bank of any stored route, which ordinarily wouldinitiate the transfer of the route storage from bank B into the nowempty bank A. However, the opening of back contact b of relay HTSinterrupts the energizing circuit for transfer relay AT so that thisrelay is not energized when relay AD releases to close its back contactb. Relay AT thus cannot pick up to initiate the transfer of the routestorage from bank B into bank A at the present time. The routes storedin banks B and C, as shown in Fig. l, are thus held inactive in thesebanks during this substitution operation, and the cancellation of thepreviously designated route for the approaching car has no. effect uponthe stored routes for the suc ceeding cars.

With relay S picked up and relay AD now released,

the energizing circuit previously described for relay SI is completedand this relay picks up, completing its stick circuit which includes thefront contact a of relay HTS. Closing of front contact e of relay SIcompletes the second energizing circuit for relay AD, which circuitincludes back contact 10, front contact e of relay SI, and themultiplied back contacts of the transfer and detector relays in thesucceeding storage banks. This circuit is completed at this time overthe back contacts of the transfer relays T which are deenergized sinceno route transfer is occurring to these succeeding banks. When relay AD,thus reenergized, picks up again, the circuits are completed forinserting the hold-track route into the storage relays of the A bank. Asshown in the drawing, with lever HT in its right-hand or track 1position, the circuit may be traced from terminal B over right-handcontact a of lever HT, front contact b of relay SI, back contact a andthe winding of relay AlC, and front contact a of relay AD to terminal N.With lever HT in this position, that is, position 1, relay A1C isenergized and picks up completing its stick circuit at its own frontcontact a to store the hold-track route to track 1. If lever HT is inits left-hand or track 2 position, the circuit would be over left-handcontact a of lever HT, front contact c of relay SI, back contact a andthe winding of relay AZC, and front contact a of relay AD to terminal N,so that relay A2C would be energized and pick up to store a route totrack 2. However, assuming that the lever HT is in its No. 1 position,relay AlC pick up to complete at its front contact b the circuit forenergizing the controls for the switch motor 1-6, shown in Fig. 1, whichoperates switch 1-6SW to its reverse position. Thus the car approachingthat switch will be diverted from its original designated route to track6 to the route to track 1.

With the hold-track route for the diverted car now stored in bank A ofthe initial storage banks, the substitution is accomplished and thecircuit previously traced for relay PC is complete. This circuit underthe present conditions includes front contact of relay A1C andright-hand contact 12 of lever HT as well as front contacts of relaysSI, AD, and HTS. It is to be understood that front contact 0 of relayA1C in this energizing circuit for relay PC is intended to represent acompleted route storage in the A bank and may in larger yards be two ormore front contacts, in series, of a corresponding number of storagerelays. Our invention is intended also to apply to this larger type ofinstallation.

When relay FC picks up, opening of its back contact a interrupts thestick circuit for relay HTS which then releases. The release of relaysHTS, opening its front contact a, interrupts the stick circuit for relaySI which follows with its release. However, back contact c of relay HTScloses before front contact e of relay SI opens, so that the stickcircuit for relay AD is completed prior to the opening of its energizingcircuit over front contact e of relay SI. Relay AD therefore holds up toretain the route storage in bank A until such time as the car passes theswitch location. Thus the control of relay AD is returned to its normalcircuit arrangements at this time and the operation of the system canresume its normal sequence. The closing of back contact 17 of relay HTSprepares the circuit for energizing relay AT, so that when conditionsare proper, route transfers from bank B may be resumed. With both relayHTS and relay SI releasing, the circuit for relay FC is interrupted andthis relay likewise releases. This resets the substitution apparatus toits normal condition as shown in the drawing and the general automaticswitching system of which this is a part returns to its normal sequenceof operation. In other words, when the car being diverted to hold track1 crosses switch 1-6SW, the route storage for that car is transferredfrom bank A to the storage banks at switch 1-2SW. Following this theroute stored in bank B of the initial storage banks for the succeeding10 car may be transferred into the A bank and the switch 1-6SW operatedaccordingly.

It has thus been shown that the apparatus embodying our inventionenables the operator of a classification yard equipped with an automaticswitching system to substitute a preselected hold-track route for apreviously designated route for a particular car, with only oneoperation being required on the part of the operator. Thus the divertingof cars from their previously designated route to a special routingbecause of unusual circumstances does not seriously interfere with thegeneral operation of the yard by the operator. Since the singleoperation required in pushing the hold-track push button does notrequire much time or effort on his part and does not claim his attentionaway from the usual operation for which he is responsible, the advantageof our invention to the operator and the improvement in operation of theentire yard because of the system of our invention will be obvious tothose familiar with such classification yards.

Although we have herein shown and described but on form of substitutionapparatus embodying our invention, it is to be understood that variouschanges and modifications may be made therein within the scope of theappended claims without departing from the spirit and scope of ourinvention.

Having thus described our invention, what we claim is:

1. In an automatic switching system, a route storage bank, comprising,in combination, storage means for storing a route code, means forsupplying a route code to said storage means when said storage means isinactive, means for interrupting the operation of said code supplyingmeans, means controlled by said interrupting means for cancelling theroute code stored in said storage means, means controlled by saidinterrupting means for storing a preselected route code in said storagemeans, and means responsive to the storage of said preselected routecode for resetting said interrupting means to restore the operation ofsaid code supplying means.

2. In an automatic switching system, a route storage bank, comprising,in combination, storage means for storing a route code, means forsupplying a route code to said storage means when said storage means isinactive, a route substitution push button, a relay, means controlled bysaid route substitution push button for energizing said relay, meanscontrolled by said relay in its energized condition for interrupting theoperation of said code supplying means, means controlled by said relayin its energized condition for cancelling the route code stored in saidstorage means, means controlled by said relay in its energized conditionfor storing a preselected route code in said storage means, and meansresponsive to the storage of said preselected route code fordeenergizing said relay to restore the operation of said code supplyingmeans.

3. In an automatic switching system, a route storage bank, comprising,in combination, storage means for storing a route code, means forsupplying a route code to said storage means when said storage means isinactive, a route substitution push button, a first relay, meanscontrolled by said route substitution push button for energizing saidfirst relay, a second relay, means controlled by said second relay inits deenergized condition for maintaining said first relay energized,means controlled by said first relay in its energized condition forinterrupting the operation of said code supplying means, meanscontrolled by said first relay in its energized condition for cancellingthe route code stored in said storage means, means controlled by saidfirst relay in its energized condition for storing a preselected routecode in said storage means, and means responsive to the stor age of saidpreselected route code for energizing said second relay, whereby saidfirst relay is deenergized and the operation of said code supplyingmeans is reastored.

4. In an automatic switching system of the type comprising a series ofroute storage banks associated with a series of track switches in aroute through a classification yard, in which a route code istransferred from one storage bank to the next as the correspondingswitch is occupied by a car, in combination, a storage transfer relayfor each of said banks, means for energizing each transfer relay whenthe switch associated with the preceding bank is occupied by a car, astorage detector relay for each of said banks, means controlled by thecorresponding transfer relayrfor energizing each detector relay, aplurality of route code storage relays for each of said banks, means forenergizing one of said route storage relays of each bank correspondingto an energized route storage relay of the preceding bank when thetransfer relay for the bank is energized and the storage detector relayfor the bank is deenergized, means controlled by the storage detectorrelay for each bank in its energized condition for maintaining energizedany previously energized route storage relay for that bank, a routesubstitution push button associated with a selected bank, a first relay,means controlled by said push button and the storage detector relay forsaid selected bank in its energized condition for energizing said firstrelay, a second relay, means controlled by said second relay in itsdeenergized condition for maintaining said first relay energized, meanscontrolled by said first relay in its energized condition for releasingthe storage detector relay for said selected bank, means controlled bysaid first relay in its energized condition for preventing theenergization of the route transfer relay for said selected bank, a thirdrelay, means controlled by said first relay in its energized conditionand the storage detector relay for said bank in its deenergizedcondition for energizing said third relay, means controlled by saidfirst relay in its energized condition for maintaining said third relayenergized, means controlled by said third relay in its energizedcondition for energizing a preselected one of the route storage relaysfor said selected bank, means controlled by said third relay in itsenergized condition for reenergizing the storage detector relay for saidselected bank, and means controlled by said preselected route storagerelay, said first relay, said third relay, and the storage detectorrelay for said selected bank in their energized conditions forenergizing said second relay.

5. An automatic switching system, comprising, in combination, a seriesof route storage banks, transfer means for transferring a route code toeach bank from the preceding bank as the previous route stored in thebank is cancelled, a route substitution push button associated with oneof said banks, means controlled by said push button for interrupting thetransfer means for the asso? ciated bank to prevent the transfer of theroute stored in the preceding bank, means controlled by saidinterrupting means for cancelling the route stored in the associatedbank, substitute route inserting means controlled by said interruptingmeans for storing a preselected route in said selected bank, and meanscontrolled by the storage of said substitute route for resetting saidinterrupting means to restore the operation of the associated transfermeans.

References Cited in the file of this patent UNITED STATES PATENTS2,700,728 Brixner et a1 Jan. 25, 1955

